Multiple PWM and port C

[HenrikOlsson]

Hi,
Took a quick look at the code you PM'd me and found this:

'If light=1 then                         ' If the variable is 1 then output full PWM to lights
'    hpwm 1,255,200        
'    hpwm 2,255,200
'endif
'If light=0 then                       ' If the variable is low then set value to 0 an turn off the lights
'    hpwm 1,0,200        
'    hpwm 2,0,200    
'endif

If this is where you're trying to set 100% dutycycle but ends up with a "jumpy" signal not at 100% then the problem is most likely that you're trying a frequency (200Hz) far below the specified minimum. If you look at the manual you'll see that for a 18F device running at 20MHz the minimum frequency is 1221Hz.

The only other place in the code where HPWM was used had a frequency of 5kHz so that should've worked - did it?

/Henrik.

[Scampy]

Hi,
Took a quick look at the code you PM'd me and found this:

'If light=1 then                         ' If the variable is 1 then output full PWM to lights
'    hpwm 1,255,200        
'    hpwm 2,255,200
'endif
'If light=0 then                       ' If the variable is low then set value to 0 an turn off the lights
'    hpwm 1,0,200        
'    hpwm 2,0,200    
'endif

If this is where you're trying to set 100% dutycycle but ends up with a "jumpy" signal not at 100% then the problem is most likely that you're trying a frequency (200Hz) far below the specified minimum. If you look at the manual you'll see that for a 18F device running at 20MHz the minimum frequency is 1221Hz.

The only other place in the code where HPWM was used had a frequency of 5kHz so that should've worked - did it?

/Henrik.

Hi,

That section had been commented out from when I was using the hardware modules. It was intended as a manual over-ride so that I could turn the lights on or off via the push of a button. I never ran the module at high frequencies as the LED driver requires a PWM frequency of 100 hz - 1khz and at 1 Khz they resonated with a high pitched sound.

The original code had

'*******************************************************************************
'Send pulses to drivers

    hpwm 1,W_PWM,200        
    hpwm 2,B_PWM,200
    
'*******************************************************************************

Where W_PWM and B_PWM increased from 0 to 255 or decreased from 255 to 0 to fade the LEDs up and down

[Scampy]

I've just tried cutting and pasting the code into a new page and renamed it - complied and loaded and got the same results when using C1 and C2 as the PWM pins. If I comment out the include "Multi_SPWM.pbp" the program runs fine, but I obviously have no outputs from the two pins.

So maybe you're right Henrik, in that there is some clash with the timing / or i2c bus ???

[HenrikOlsson]

Hi,
Since it seems to work when you're using SPWM on one port (PortB for example) while the I2C is on another (PortC) I don't think it's a timing thing.
Since it does NOT seem to work when the SPWM is on the SAME port as the I2C I think it's some other sort of interference where the SPWM is messing with the I2C pins, possibly due to R-M-W but I don't know for sure.

As for the hardware PWM....

The original code had

'*******************************************************************************
'Send pulses to drivers

    hpwm 1,W_PWM,200        
    hpwm 2,B_PWM,200
    
'*******************************************************************************

Well, then that IS the problem you're having - you're trying to run it at TO LOW frequency, which was the point I was trying to make.
At 20MHz oscillator frequency there is no way to actually get 200Hz from the CCP module, the lowest possible frequency is 1221Hz.

/Henrik.

[Scampy]

Ok I've tried a different approach. I noticed that Darrel has revised his multiple PWM Routine Called SPMW_INT rather then the Multi_SPWM So I modified a fresh copy of the code, included that file and the DT_INTS-18 file and the thing compiled. Loaded it to the chip and both the TEMP and CLOCK are acting up. The temp is shown as 163c and the clock as 45:85.

Here's the main part of the revised code

ASM 
  __CONFIG    _CONFIG1H, _OSC_HS_1H
  __CONFIG    _CONFIG2L, _PWRT_ON_2L  
  __CONFIG    _CONFIG2H, _WDT_ON_2H & _WDTPS_512_2H
  __CONFIG    _CONFIG3H, _MCLRE_ON_3H & _LPT1OSC_OFF_3H & _PBADEN_OFF_3H  
  __CONFIG    _CONFIG4L, _LVP_OFF_4L & _XINST_OFF_4L
ENDASM

INCLUDE "DT_INTS-18.bas"            ; Base Interrupt System
INCLUDE "SPWM_INT.bas"              ; Software PWM module

DEFINE SPWM_FREQ  200                ; SPWM Frequency
DEFINE SPWM_RES   256               ; SPWM Resolution

ASM
SPWM_LIST  macro                    ; Define Pin's to use for SPWM
     SPWM_PIN  PORTC, 1, _B_PWM  ; and the associated DutyCycle variables
     SPWM_PIN  PORTC, 2, _W_PWM  ; Notice the underscore before variables

  endm
  SPWM_INIT  SPWM_LIST              ; Initialize the Pins
ENDASM

ASM
INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler   TMR1_INT,  SPWMhandler,  ASM,  yes
    endm
    INT_CREATE                      ; Creates the interrupt processor
ENDASM

@ INT_ENABLE  TMR1_INT              ; enable Timer 1 interrupts


INCLUDE "LCDbar_INC.bas"        ' Include the BARgraph routines
 

DEFINE LCD_DREG  PORTB                  ' LCD Data port
DEFINE LCD_DBIT  0                      ' starting Data bit (0 or 4)
DEFINE LCD_EREG  PORTB                  ' LCD Enable port
DEFINE LCD_EBIT  5                      '     Enable bit  (on EasyPIC 5 LCD)
DEFINE LCD_RSREG PORTB                  ' LCD Register Select port
DEFINE LCD_RSBIT 4                      '     Register Select bit   (on EasyPIC 5 LCD)
DEFINE LCD_BITS  4                      ' LCD bus size (4 or 8 bits)
DEFINE LCD_LINES 4                      ' number of lines on LCD
DEFINE LCD_COMMANDUS 2000               ' Command delay time in us 
DEFINE LCD_DATAUS 50                    ' Data delay time in us 

DEFINE  OSC 20                          ' 18F4520, 20mhz crystal
ADCON1 = $0F
clear

'*******************************************************************************
'DS18B20 temp probe setting
'*******************************************************************************

DQ              VAR     PORTA.5         ' One-wire data pin
temperature     VAR     WORD            ' Temperature storage
count_remain    VAR     BYTE            ' Count remaining
count_per_c     VAR     BYTE            ' Count per degree C

'*******************************************************************************
'Port and Register settings
'*******************************************************************************
   
TRISA  = %11101111              
TRISB  = %00000011 
TRISD  = %00000011              
T0CON  = %11000111

ADCON0 = %00000000;          // AD converter module disabled
ADCON1 = %00001111;          // All Digital
ADCON2 = %00000000;          // 
CMCON = 7   

'*******************************************************************************
' Data presets
'*******************************************************************************
data @0
    data    00                          'Blue fade IN duration hours
    data    5                          'Blue fade IN duration minutes
    data    00                          'Blues fade OUT duration hours
    data    45                          'Blue fade OUT duration minutes
    data    00                          'Whites fade IN duration hours
    data    7                          'Whites Fade IN duration MINS
    data    00                          'Whites Fade OUT duration HOURS
    data    20                          'Whites Fade OUT duration MINS
    data    255                         'Blue MAX Intensity %
    data    255                         'Whites MAX Intensity %
    data    word 840                    'Blue ON time 14:00
    Data    word 840                    'Whites ON time 14:00
    data    word 1200                   'Blue OFF time  20:00
    Data    word 1200                   'White OFF time 20:00
    Data    word 1200                   'Sump light on time  20:00
    Data    word 1200                   'Sump light off time  8:00
   
            
'*******************************************************************************
' Variables
'*******************************************************************************

fadesetHR          VAR WORD[2]                   
  fadesetHR1       VAR fadesetHR[0]     'blue fade in hour
  fadesetHR2       VAR fadesetHR[1]     'White fade in hour
  
fadesetMN          VAR WORD[2]                   
  fadesetMN1       VAR fadesetMN[0]     'blue fade in minutes
  fadesetMN2       VAR fadesetMN[1]     'white fade in minutes
  
fadeoutHR          VAR WORD[2]                   
  fadeoutHR1       VAR fadeoutHR[0]     'blue fade out hour
  fadeoutHR2       VAR fadeoutHR[1]     'white fade out hour
  
fadeoutMN          VAR WORD[2]                   
  fadeoutMN1       VAR fadeoutMN[0]     'blue fade out minute
  fadeoutMN2       VAR fadeoutMN[1]     'white fade out minutes
  
lightsetHR          VAR word[2]                   
  lightsetHR1       VAR lightsetHR[0]   'blue on time hour
  lightsetHR2       VAR lightsetHR[1]   'white on time hour
  
lightsetMN          VAR word[2]                   
  lightsetMN1       VAR lightsetMN[0]   'blue on time minutes
  lightsetMN2       VAR lightsetMN[1]   'white on time minutes
  
lightoffHR          VAR word[2]                   
  lightoffHR1       VAR lightoffHR[0]   'blue off time hour
  lightoffHR2       VAR lightoffHR[1]   'white off time hour
  
lightoffMN          VAR word[2]                   
  lightoffMN1       VAR lightoffMN[0]   'blue off time minutes
  lightoffMN2       VAR lightoffMN[1]   'white off time minutes


DecButton var PORTA.0	                ' Press to Decrement Button
SetButton var PORTA.1                   ' Press to Set/memorise Button
IncButton var PORTA.2	                ' Press to Increment Button

OnButton var PORTA.0	                ' Press to Decrement Button
OffButton var PORTA.2	                ' Press to Increment Button

H_butt   VAR PORTA.2                    'hour increase 
M_butt   VAR PORTA.0                    'minutes increase
S_butt   VAR PORTA.1                    'set / memorise

Counter1 var word                       'used to store the current time as a digit.  Counts minutes from 0000 at midnight

Blue_on_Time var word                   'stores the blue on time as a digit in minutes, eg 14:00hrs = 840
Blue_off_Time var word                  'stores the blue off time as a digit in minutes, eg 14:00hrs = 840
White_on_Time var word                  'stores the white on time as a digit in minutes, eg 14:00hrs = 840
White_off_Time var word                 'stores the white off time as a digit in minutes, eg 14:00hrs = 840

white_delay_in var byte                 'stores the white fade in pule in seconds
blue_delay_in VAR byte                  'stores the blue fade in pule in seconds
white_delay_out var byte                'stores the white fade out pule in seconds
blue_delay_out VAR byte                 'stores the blue fade out pule in seconds

W_Min           var byte                'Min Light value - Whites
W_Max           var byte                'Max Light value - Whites
B_Min           var byte                'Min Light value
B_Max           var byte                'Max Light value

Old_B_Max var byte
Old_W_Max var byte

W_PWM           var word                'PWM Variables where the current output values are stored - Whites
B_PWM           var word                'PWM Variables where the current output values are stored - Royal Blues

old_ss_blue     var byte                'records the previous second in blue fade in
old_ss_white    var byte                'records the previous second in white fade in

option          var byte                'menu option, used to choose which menu option is required   

Viv             var byte                'used to select the channel the menu selection applies to
maxbright       var byte                'general variable used to set the max brighness for each channel in menu option

fn              var byte                'general variable to switch between channels in menu options
Hours           var byte                'used in menu options to set hours for each channel
Minutes         var byte                'used in menu options to set minutes for each channel
light           var byte

Sumplighton     Var word                'counter variable for sump on time
Sumplightoff    Var Word                'counter vairable for sump off time
Sump_light      Var PORTA.4             'sump light pin     
sumponHR        VAR byte                'sump light on Hour
sumponMN        var byte                'sump light on Minutes
sumpoffHR       var byte                'sump light off Hours
sumpoffMN       var byte                'sump light off Minutes

daycount        var byte

TimeH           var byte                'variable to store Hours
TimeM           var byte                'variable to store Minutes
SS              VAR Byte                'variable to store Seconds

RTCsec          var byte                'RTC Seconds
RTCMin          var byte		        'RTC Minutes
RTCHour         var byte	            'RTC Hours
SetMN           var byte		        'Used to set time Minutes
SetHR           var byte	            'Used to set time Hours
SetSS           var byte                'Used to set time Seconds 
                   
SCLpin          var PORTC.3             'RTC pin - clk
SDApin          var PORTC.4             'RTC pin - data

CounterA        var byte	            'General purpose Variable
CounterB        var byte	            'General purpose Variable
CounterC        var byte	            'General purpose Variable
CounterD        var byte	            'General purpose Variable

FlashStar       VAR BIT

Blue_Day_Cycle      var word            'Store for which part of the blue day cycle we are in
White_Day_Cycle     var word            'Store for which part of the white day cycle we are in


DAWN    con     0                       'Constants for the current running mode cycle for the lights
DAY     con     1
DUSK    con     2
NIGHT   con     3

'*******************************************************************************
;Initialization

LCDOUT $FE,1:FLAGS=0:PAUSE 250:LCDOUT $FE,1:PAUSE 250 ' Initialize LCD
LCDOUT  $FE,1
lcdout  $FE,$C0,"   Firmware v1.07   "
pause   2000                            'wait 2 seconds so they can see it
lcdout  $FE,1                           'Clear the screen

Gosub read_eprom                        'read in presets for fade in durations and brighness

blue_delay_in = (((fadesetHR[0]*60)+fadesetMN[0])*60)/255   'takes hours and minutes, converts to minutes, then converts to seconds
white_delay_in = (((fadesetHR[1]/60)+fadesetMN[1])*60)/255  'takes hours and minutes, converts to minutes, then converts to seconds
blue_delay_out = (((fadeoutHR[0]/60)+fadeoutMN[0])*60)/255  'takes hours and minutes, converts to minutes, then converts to seconds
white_delay_out = (((fadeoutHR[1]/60)+fadeoutMN[1])*60)/255 'takes hours and minutes, converts to minutes, then converts to seconds

Option = 1                              'sets the menu option default as 1 (set time)
daycount=0                              'used in sumplight routine to check if gone passed midnight

Sumplightoff =1439
Sumplighton  =1439                      'sumplight - values used to match counter1 for on off times

setHR = 13                              'initial time following programming or re-boot if RTC not battery backed up
setMN = 59

'convert initial time to BDC and write it to the DS1307
CounterA=SetMN
Gosub ConvertBCD
RTCMin=CounterB

CounterA=SetHR
Gosub ConvertBCD
RTCHour=CounterB

I2Cwrite SDApin,SCLpin,$D0,$00,[RTCSec,RTCMin,RTCHour] 



'*******************************************************************************
'************                     Main Program Loop              ***************
'*******************************************************************************

Main:

If SetButton=0 then                     'if presed jump to the menu
goto mainmenu
endif

'*******************************************************************************
' check for manual override of the lights
If H_butt = 0 then                      ' if pressed then change state of varible to 1
Light=1
endif

If M_butt = 0 then                      ' if pressed then change state of varible back to 0
Light=0
endif
'*******************************************************************************
'clock routine
   
I2CREAD SDApin,SCLpin,$D0,$00,[RTCSec,RTCMin,RTCHour]  ; read DS1307 chip

timeH=(RTCHour>>4)                        'convert the BCD format of the hours register and store in variable timeH
timeH=(timeH &$03)*10
timeH=timeH+(RTCHour&$0F)

timeM=(RTCMin>>4)                         'convert the BCD format of the mins register and store in variable timeM
timeM=(timeM &$07)*10
timeM=timeM+(RTCMin&$0F)    

ss=(RTCSec>>4)                            'convert the BCD format of the sec register and store in variable ss
ss=(ss &$07)*10
ss=ss+(RTCSec&$0F)                     

Counter1 = (TimeH *60)+ TimeM             'take hours and multiply it by 60 then add odd minutes to get the total minutes into counter1

LCDOut $FE,$D4+15,#TimeH DIG 1,#TimeH DIG 0,":",#TimeM DIG 1,#TimeM DIG 0
             
 
'*******************************************************************************
' check to see if the sump light should be on or off

If daycount = 0 THEN                    ' by default daycount is 0
   If Counter1 => sumplighton Then      ' if the counter matched the sump light on time
     high sump_light                    ' then make the pin high and
     daycount = 1                       ' set the day count to 1
  ENDIF
ENDIF

IF daycount = 1 THEN                    ' if the daycount is 1 and
  If Counter1 = sumplightoff Then       ' conuter matches sump light off time
    low sump_light                      ' then make the pin low and
    daycount = 0                        ' reset daycount back to 0                       
  ENDIF
ENDIF

'*******************************************************************************
'Case Cycle logic 

If Counter1 < Blue_on_Time then
Blue_day_cycle = NIGHT
endif

if counter1 > blue_on_time and Counter1 > blue_off_Time and B_PWM > B_Min then
Blue_day_cycle = DUSK
endif

if counter1 => blue_on_time and Counter1 < blue_off_Time and B_PWM < B_MAX then
Blue_day_cycle = DAWN
endif


If Counter1< White_on_Time then
White_day_cycle = NIGHT
endif

if counter1 > white_on_time and Counter1 > white_off_Time and W_PWM > W_Min then
White_day_cycle = DUSK
endif

if Counter1 => white_on_time  and Counter1 < white_off_Time and W_PWM < W_MAX then
White_day_cycle = DAWN
endif

'*******************************************************************************
'BLUE daily cycle

select case Blue_Day_Cycle
    
case DAWN 
lcdout $FE,$80+15,"DAWN "   
if ss//blue_delay_in = 0 then
if ss != old_ss_blue then
B_PWM=B_PWM+1
old_ss_blue=ss
endif
endif
if B_PWM = b_max then
Blue_Day_Cycle = DAY
endif

case DAY
lcdout $FE,$80+15,"DAY  "
if B_max < B_PWM then
B_PWM=B_PWM - 1
endif 
if counter1 =blue_off_time then
Blue_day_cycle = DUSK
endif
    
CASE DUSK
lcdout $FE,$80+15,"DUSK "
if ss//blue_delay_out= 0 then
if ss != old_ss_blue then
B_PWM=B_PWM-1
old_ss_blue=ss
endif
endif
if B_PWM = B_MIN then 
Blue_Day_Cycle = NIGHT
endif

case NIGHT
lcdout $FE,$80+15,"NIGHT"
B_PWM=B_min
end select

'*******************************************************************************
'WHITE daily cycle

select case White_Day_Cycle
    
case DAWN 
lcdout $FE,$C0+15,"DAWN "   
if ss//white_delay_in= 0 then
if ss != old_ss_white then
W_PWM = W_PWM+1
old_ss_white=ss
endif
endif
if W_PWM = W_max then
White_Day_Cycle = DAY
endif

case DAY
lcdout $FE,$C0+15,"DAY  "
if W_max < W_PWM then
W_PWM=W_PWM - 1
endif
if counter1 =white_off_time then
White_day_cycle = DUSK
endif
    
CASE DUSK
lcdout $FE,$C0+15,"DUSK "
if ss//white_delay_out= 0 then
if ss != old_ss_white then
W_PWM=W_PWM-1
old_ss_white=ss
endif
endif
if W_PWM = W_min then 
White_Day_Cycle = NIGHT
endif

case NIGHT
lcdout $FE,$C0+15,"NIGHT"
W_PWM=W_min
end select

'*******************************************************************************
'tidy up the display for the current percentage to remove stray zero's

If (B_PWM * 100)/255 = 100 then
lcdout $FE,$80,"BL ",$FE,$80+3,dec3 (B_PWM *100)/255,"%"
endif

If (B_PWM * 100)/255 =0 or (B_PWM * 100)/255 <10 then
lcdout $FE,$80,"BL ",$FE,$80+3,dec1 (B_PWM *100)/255,"% "
endif

if (B_PWM * 100)/255 >=10 and (B_PWM * 100)/255 <100 then
lcdout $FE,$80,"BL ",$FE,$80+3,dec2 (B_PWM *100)/255,"%  "
endif

If (W_PWM*100)/255 >= 100 then
lcdout $FE,$C0,"WT ",$FE,$C0+3,dec3 (W_PWM *100)/255,"%"
endif

If (W_PWM * 100)/255 <=0 or (W_PWM * 100)/255 <10 then
lcdout $FE,$C0,"WT ",$FE,$C0+3,dec1 (W_PWM *100)/255,"% "
endif

if (W_PWM * 100)/255 >=10 AND (W_PWM * 100)/255 <100 then
lcdout $FE,$C0,"WT ",$FE,$C0+3,dec2 (W_PWM *100)/255,"%  "
endif
'*******************************************************************************
'Get and display the temperature

    OWOUT DQ, 1, [$CC, $44]                 ' Start temperature conversion
    OWOUT DQ, 1, [$CC, $BE]                 ' Read the temperature
    OWIN DQ, 0, [temperature.LOWBYTE, temperature.HIGHBYTE]
    temperature = temperature */ 1600
    lcdout $FE,$D4+0,"TEMP ",DEC(temperature / 100),$DF,"C"
'*******************************************************************************
'generate bar graph on LCD

    ; syntax- BARgraph   Value, Row, Col, Width, Range, Style
   @         BARgraph  _B_PWM,   1,   8,    6,   255,  lines
   @         BARgraph  _W_PWM,   2,   8,    6,   255,  lines

  
GOTO Main

Darrels code seems to allow frequencies of 100hz which makes this ideal.... if it can be made to work

I appreciate all your help....Hopefully Darrel can shed some light

Oh and meant to add that it runs really slowly (displays the firmware splash screen for around fifteen seconds rather than the three or so

[HenrikOlsson]

Hi,
The reason it runs slow is due to the interrupt driven PWM routines. You have a PWM frequency of 200Hz and a resolution of 256 steps, this results in an interrupt frequency of 51200Hz.
According to Darrels page (if I'm on the right one) each "PWM-channel" needs 20 instructions - in your case 51200 * 20 * 2 = 2,048,000 instructions per second, just for running the 2 PWM channels. At 20MHz there's 5,000,000 instructions per second to play with which means that 40% of the processors time is spent running the PWM.

You tell PBP that you're running at 20MHz but then the assembly interrupts silently eats away 40%.

In this case each and every Hz you decrease the PWM frequency will give more time to the actual PBP program, if 100Hz is "all" you need then don't try running it at 200Hz. But again, it doesn't seem to be the timing per se that makes it NOT work since it using different ports for the PWM and I2C works.

/Henrik.

[Scampy]

Thanks for the explanation...

I think I'll go back to using port D for the outputs and revert back to the mulit_swpm file. Not ideal, as I'll have to modify the PCB, but at least it works without the delays or screwing up the clock etc. If I get chance I'll try this on the old 16F877A chip rather than an 18F to see if this issue is chip related...

[Scampy]

I've recorded the wave form when using the hardware PWM modules on the chip to explain the issue I'm getting.



If you compare this to using the multi_swpm file and port D you notice there are loads of spikes in the HWPM signal and some harmonics ? - the amplitude is also a lot less (I had to increase the volume for the HWPM to get a similar trace)